Mutant allele of watercress

ABSTRACT

The present invention relates to a new and distinct variety of watercress plant, and its plant parts, including the mutation of an allele of watercress designated “BWRW”, which results in watercress plants with red-pigmented leaves and/or stems. The red-green variety is distinguished from green watercress varieties, in particular with its red pigmentation ranging from dark purple, dark red to pink leaves and stems; intermediate-sized stem diameter ranging from 3.5 mm to 5.5 mm, which is commercially acceptable for both fresh and cooked consumption; a nutritional antioxidant capacity of at least 2.27 times greater than compared standard U.S. and U.K. green watercress varieties; and expanded harvesting seasons, with suitability to be grown in the United States year-round.

CROSS REFERENCE

This application is a continuation of application Ser. No. 12/611,276,filed on Nov. 3, 2009, which claims priority to application Ser. No.61/111,247, filed on Nov. 4, 2008 which are each hereby incorporated byreference in their entirety and for all purposes.

LATIN NAME OF THE GENUS AND SPECIES OF THE PLANT CLAIMED

The watercress variety of this invention is botanically identified asNasturtium officinale W. T. Aiton.

VARIETY DENOMINATION

The variety denomination is ‘RW1’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct variety ofwatercress plant and its plant parts, including the mutation of anallele of watercress designated “BWRW”, which results in watercressplants with red-pigmented leaves and/or stems.

Watercress is also known as Nasturtium officinale W. T. Aiton and itbelongs to the family Brassicaceae (formerly the Cruciferae family).Watercress is native to Europe and Asia, common in Great Britain andwidely naturalized in the United States and Canada. It has also beenintroduced into the West Indies and South America. It is reported thatNicholas Messier first grew watercress in Erfurt, Germany in the middleof the 16th century. English cultivation started in the early 1800s,when a farmer near London began to grow watercress for use in salads. Itwas not long before its popularity spread. Today the crisp green sprigsof watercress are commonly eaten out of hand, combined with other tendergreens in salads and used as a garnish on hot and cold dishes.

The foregoing examples of the related art and limitations relatedtherewith are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification.

BRIEF SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described inconjunction with systems, tools and methods which are meant to beexemplary, not limiting in scope. In various embodiments, one or more ofthe above-described problems have been reduced or eliminated, whileother embodiments are directed to other improvements.

The following traits have been repeatedly observed and represent thecharacteristics of the new and distinct variety of red watercress plantnamed ‘RW1’. These traits in combination distinguish this variety fromall other commercial varieties known to the inventor.

-   -   1. In addition to green, a plant having red pigmentation of        leaves and/or stems, with red coloration ranging from dark        purple, dark red to pink;    -   2. An average intermediate-sized stem diameter of 3.5 to 5.5 mm,        which is commercially acceptable for both fresh and cooked        consumption;    -   3. A nutritional antioxidant capacity of at least 2.27 times        greater than compared green watercress varieties; and    -   4. Expanded harvest season, with suitability to be grown in the        United States year-round.

Plants of the present invention have not been observed under allpossible environmental and cultural conditions. The phenotype will varysomewhat with variations in environmental conditions, for example, withfluctuation in temperature and photoperiod, without, however, anyvariance in genotype.

According to the invention, there is provided a new and distinct varietyof red watercress plant named ‘RW1’, and its plant parts, including itsmutant allele designated “BWRW”. This invention thus relates to thewatercress which comprises a mutant allele which results inred-pigmentation on leaves and/or stems.

In another aspect, the present invention provides regenerable cells foruse in tissue culture. The tissue culture will preferably be capable ofregenerating plants having the physiological and morphologicalcharacteristics of the foregoing watercress plant, and of regeneratingplants having substantially the same genotype as the foregoingwatercress plant. Still further, the present invention provideswatercress plants regenerated from the tissue cultures of the invention.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by study of thefollowing descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying photographs show two typical specimens of the newvariety, including the leaves and stems demonstrating the pigmentationvariation produced by the mutant allele designated BWRW. The photographswere taken of four-week-old harvested plants from different locations inthe same bed. The different specimens demonstrate the variation inpigment distribution as occurs with variations in environmentalconditions, such as exposure to day length or photoperiod. Thephotographs were taken outdoors, under natural light conditions, nearmid-day on a sunny, late summer day.

FIG. 1 shows the first plant specimen, demonstrating dominantdark-purple pigmented leaves and dark reddish-green stems. The moreuniform pigmentation occurrence on plant structures is more typical offall and winter months, or in areas with a shortened photoperiod.

FIG. 2 shows a section of the stem of the first plant specimen,demonstrating dark-purple to deep-reddish-green pigmentation and leaveswith significant red pigmentation and green veins.

FIG. 3 shows a closely cropped image of the first plant specimen withred and green coloration of a section of the stem and leaves withsignificant red pigmentation, and green veins.

FIG. 4 shows a plant leaf from the first plant specimen, demonstratingdominant red pigmentation on the blade with distinctly green veins.

FIG. 5 shows the second plant specimen, demonstrating green coloredstems and mostly green leaves with red pigmentation mainly distributedon leaf borders. The broadened green coloration on plant structures ismore typical of summer months, or in areas with a lengthenedphotoperiod.

FIG. 6 shows the second plant specimen with green stem and green leaveswith scarce red pigmentation mainly distributed on leaf borders.

FIG. 7 shows a closely cropped image of the second plant specimen withgreen stem and green leaves with scarce red pigmentation mainlydistributed on leaf borders.

FIG. 8 shows an image of a leaf from the second plant specimen,demonstrating significant green coloration on the blade with scarce redpigmentation mainly distributed on leaf borders.

DEFINITIONS

In the description and tables that follow, a number of terms are used.In order to provide a clear and consistent understanding of thespecification and claim, the following definitions are provided:

Allele. An “allele” is any of one or more alternative form of a gene(dominant or recessive), all of which alleles relates to one trait orcharacteristic gene.

BWRW. “BWRW” refers to the mutant allele or alleles of the presentinvention that results in red-pigmented leaves in the watercress plantnamed ‘RW1’.

Essentially all the physiological and morphological characteristics. Aplant having “essentially all the physiological and morphologicalcharacteristics” means a plant having the physiological andmorphological characteristics, except for the characteristics derivedfrom the converted gene or genes.

Regeneration. “Regeneration” refers to the development of a plant fromtissue culture.

Yield. The term “Yield” is typically defined when used. Yield can meanthe number of bunches of watercress per acre where, on average, 4bunches equal approximately a pound. Alternatively, if watercress isharvested loose, yield may be measured in pounds (lbs) or kilograms (Kg)per acre.

DETAILED BOTANICAL DESCRIPTION

The present invention relates to a new and distinct variety of redwatercress plant and its plant parts, including the mutation of alleledesignated “BWRW” in the genus Nasturtium that is phenotypicallydescribed in the present invention via a watercress plant havingred-pigmented leaves and/or stems.

Watercress is a perennial plant and is generally produced for humanconsumption. Watercress is typically grown in rectilinear beds withflowing water and the beds are tested frequently for the presence ofharmful pathogens. The flowing water may flow through the bed and exitor it may be re-circulated to flow through multiple times. Companies mayalso add a proprietary blend of fertilizer elements to the irrigationwater in the flow-through system. Each bed will have a base to supportwatercress root growth. The base composition may be natural soil, whichis commonly used in the United States, soil overlaid with pebbles, whichis commonly used in England, or various plastic compounds overlaid witha more porous material that roots can hook on to.

Watercress may be propagated via vegetative stem cuttings on beds withrunning water or the crop can be seeded. When the seedlings are ofappropriate size they are scooped up and flung randomly onto the bed'ssurface. Additionally, the crop can be directly seeded on beds by aprecision seeder or drill. Typically the first crop reaches aharvestable stage in about 7 weeks with subsequent harvests occurring at4 to 5 week intervals depending on environmental conditions. Harvest canoccur by hand making a bunch in the field and placing a rubber bandaround the bunch and trimming the end to the desired length.

Watercress is often used to make tea or to make a stock base forcooking. It is also frequently used in place of lettuce on sandwiches.More recently chefs have begun offering watercress in salads and thered-pigmented watercress provides chefs and other food preparers with astriking color option when adding watercress to typically green salads.In addition, members of medical research communities in the U.S. andU.K. have begun detailing the varied anticancer properties ofwatercress.

The present invention provides a mutant allele designated “BWRW” whichresults in watercress plants having red-pigmented leaves and/or stems.The red pigmentation of the leaves can range in appearance from darkpurple and dark red to pink depending on the environmental conditionsand whether one is looking at the upper or lower surface of the leaf

In addition to conferring the red pigment to the leaves and/or stems,the BWRW allele also affects the distribution of the pigment in theleaves depending on the maturity of the crop and variation in theenvironmental conditions such as with fluctuations of photoperiod duringdifferent times of the year. The red color is distributed mainly in theleaf blade while the veins remain bright green under a short photoperiod(less than 10 h), and for example, when grown in Florida wheretemperatures fluctuate between 30° and 50° F. during cooler months. Ingrowing conditions under a long photoperiod (longer than 10 h), forexample in northern latitudinal areas where temperatures range between89° and 105° F., the red color is distributed largely at the leafmargins while the veins and the leaf blades are bright green.

EXAMPLES

The following examples are provided to further illustrate the presentinvention and are not intended to limit the invention beyond thelimitations set forth in the appended claim.

Example 1. Development of BWRW, the Mutant Allele of the PresentInvention

The mutant allele of the embodiments of the present invention, BWRW,unexpectedly arose as a spontaneous mutation in a population of triploidgreen watercress grown in New Market, Ala. during the Summer of 2006.Prior to the present invention, a red-pigmented leaf mutation of thistype in watercress was unknown. The single, large, mutant plant wasmoved from Alabama to Fellsmere, Fla. and placed in a research bedduring the Winter-Spring season of 2006-2007. The line was expanded viastem cuttings to create an 8′×40′ bed. Additional expansion tocommercial sized beds of about 6 acres in size was again accomplishedvia stem cuttings. In each 6-month period the line was uprooted andtransferred between Alabama and Florida for further reproduction.Additionally, the ‘RW1’ line is maintained through a tissue cultureprogram to maintain healthy plants free of pests and pathogens.

Example 2. Morphological Description

The red-pigmented watercress of the present invention has shownuniformity and stability for red-pigmented leaves and/or stems and othertraits substantially as shown and described herein, within the limits ofenvironmental influence for pigmentation. The line has been increasedthrough at least 20 crop cycles since 2006 with continued observationfor uniformity. No variant traits have been observed or are expected inthe present invention. The red-pigmented watercress of the presentinvention has the following morphologic and other characteristics.

TABLE 1 VARIETY DESCRIPTION Plant: A perennial succulent temperate herbStems: Appearance: Floating and semi-erect stems, typically stays underwater while 17.78 cm (7.0 in) turns upward when ready for harvestDiameter: 3.5 to 5.5 mm diameter at 17.145 cm (6.75 in) from apicalmeristem Internode length: 1.27 cm (0.5 in) Leaves: Arrangement: Acompound leaf with two opposite pair of oval leaflets and a pentagonshaped terminal leaflet Apex: Moderately apiculate Base: Inequilateraltruncate to round Margin: Crenate to sinuate Color (between 30° and 50°F., during cooler months, or 10 hour photoperiod or less): Immature:Upper surface: RHS 186A (purple-grey) interveinal cells with RHS 142A(green) veins Lower surface: RHS 77A (purple) interveinal cells with RHS142A (green) veins Mature: Upper surface: RHS 186A (burgundy) throughoutthe interveinal area with RHS 142A (green) veins Lower surface: RHS 77A(purple) throughout the interveinal area with RHS 142A (green) veinsColor (89° and 105° F. during warmer months, or long day photoperiod):Leaf margins RHS 186A, rest of tissue RHS 142A (green) Inflorescence:Appearance: Raceme Floral cycle: One flower/seed production cycle duringsummer and winter per floral induction treatment Flower petal color:White Fruit: Linear cylindrical silique

COMPARISON TO SIMILAR VARIETIES Tables

Watercress plants grow as long indeterminate stems which may elongate ina prostrate or upright orientation. Prostrate forms usually root intosupport media at the axils while simultaneously producing a lateral stemwhich orients upright for harvest. Upright forms bend upright forming anL shape without long prostrate runs. Unexpectedly, the red watercressplant named ‘RW1’, containing the BWRW mutant allele of the presentinvention presents an intermediate form, grows more slowly than standardgreen watercress, and produces 36% fewer marketable stem bunches thanstandard 3 n or 2 n green watercress lines. Table 2 shows the yield ofthe red watercress plant named ‘RW1’, containing the BWRW mutant alleleof the present invention as compared to the yield of standard greenwatercress plants. In Table 2, column 1 shows the type of watercress,column 2 shows the ploidy, column 3 shows the year, columns 4 through 12show the yield in bunches per acre and column 13 shows the mean yieldfor each year.

TABLE 2 Comparison of Red Watercress Plant Named ‘RW1’ Containing theBWRW Mutant Allele with Standard Green Watercress Lacking the BWRWMutant Allele for Yield over Two Years Four Week Periods BeginningJanuary 1 Watercress Line Ploidy Year 1 2 3 4 5 6 11 12 13 Mean RedWatercress 3n 2008 18,800 12,770 16,529 7,336 16,592 15,771 15,52011,919 14,405 Plant Named ‘RW1’ 2009 15,750 13,730 19,226 15,270 8,99614,594 Green Watercress 3n 2008 21,732 23,823 25,354 22,850 27,30322,900 21,495 21,223 18,795 22,841 USA Standard 2009 16,151 25,35322,588 23,979 25,228 23,196 22,749 Green Watercress 2n 2008 18,25718,782 20,862 21,674 26,828 21,234 15,808 17,800 20,156 UK Standard 200927,433 26,269 18,401 20,982 23,271

As shown in Table 2, the red watercress plant named ‘RW1’, containingthe mutant allele BWRW of the present invention unexpectedly yieldedsignificantly fewer bunches per acre than either the standard U.S. orU.K. green watercresses which lack the BWRW mutant allele. Importantly,while slower growth reduces the total number of bunches and crops perseason, slower growth allows the crop to hold longer in the field beforegoing out of market specifications. An additional benefit is thatindividual stems do not develop as large an undesirable central hole asfaster growing lines do.

Watercress stem diameters affect how watercress is used by consumers.Watercress can be consumed fresh as a lettuce substitute or in a mix offresh greens; it can be boiled, sautéed or stir-fried. Watercress linesmarketed for fresh consumption typically possess a smaller stemdiameter, for example in the U.K. where watercress is most oftenconsumed fresh, the standard stem diameter is 2.33 mm. Watercress linesmarketed for stir fry, boiling, or sautéing possess larger stemdiameters of 3.5 to 5.5 mm. Unexpectedly, the red watercress plant named‘RW1’, containing the BWRW mutant allele of the present invention had amean stem diameter that was intermediate between the green standard U.S.watercress line and the green standard U.K. watercress line.

Table 3 shows the mean stem number per bunch, the mean weight per stem,and the mean stem diameter for red watercress plant named ‘RW1’, whichcontains the BWRW mutant allele of the present invention as compared tostandard U.S. and U.K. green watercresses which lack the BWRW mutantallele. Also included are two experimental green watercresses, 47-8 and96-1, which lack the BWRW mutant allele of the present invention. InTable 3 column 1 shows the watercress line, column 2 shows the ploidy ofeach line, column 3 shows the growing location, column 4 shows the datethe watercress was cut and the measurements taken, column 5 shows themean stem number per bunch, column 6 shows the mean weight in grams perstem, column 7 shows the mean stem diameter in millimeters, and column 8shows the standard deviation of the stem diameter in millimeters.

TABLE 3 Comparison of Various Stem Characteristics between RedWatercress Plant Named ‘RW1’, Containing the BWRW Mutant Allele andStandard Green Watercress and Two Experimental Watercress Lines MeanMean Stem Stem # Mean Stem Diameter, per Wt per Diameter Std WatercressLine Ploidy Location Cut Date Bunch Stem (g) (mm) Dev (mm) RedWatercress Plant 3n Florida Jan. 12, 2009 34 4.68 4.39 1.11 Named ‘RW1’Red Watercress Plant 3n Tennessee Jun. 5, 2009 49 4.14 3.58 1.26 Named‘RW1’ Green Watercress US 3n Florida Jan. 12, 2009 42 3.59 3.60 1.09Standard Green Watercress US 3n Tennessee Jun. 5, 2009 45 4.63 4.06 1.22Standard Green Watercress UK 2n Florida Jan. 14 2009 91 1.57 2.33 0.76Standard 47-8 6n Florida Jan. 12, 2009 44 3.48 3.39 1.02 47-8 6nTennessee Jun. 5, 2009 32 6.64 5.37 1.27 96-1 6n Florida Jan. 12, 200928 5.99 4.46 1.11 96-1 6n Tennessee Jun. 5, 2009 48 4.86 3.86 1.10

As shown in Table 3, the red watercress stem diameter, 3.58 to 4.39 mm,compares favorably with the U.S. standard 3 n line, 3.6 to 4.06 mm, andwith two new experimental hexaploid lines.

The red watercress plant named ‘RW1’, containing the BWRW mutant alleleof the present invention unexpectedly can be grown in the U.S. in summerbecause its stem diameter range of 3.5 to 5.5 mm is commerciallyacceptable for a variety of uses by consumers. The stem diameter of thered watercress containing the BWRW mutant allele of the presentinvention is such that it is not too small to be used for stir-fry,boiling and sautéing nor is it too big to be used for fresh consumption.As shown in Table 3, the BWRW allele allows watercress to be grownyear-round unlike the standard green U.K. watercress.

The assay Ferric Reducing Ability of Plasma (FRAP) is considered anassay of antioxidant power. In tests at the University of South Hampton,U.K., watercress FRAP values of a number of watercress lines were testedand ranged from 1.61 to 5.65 nmol Fe 2+ equivalents per gram freshweight. In these tests red watercress plant named ‘RW1’, containing theBWRW mutant allele of the present invention had an unexpected FRAP valueof 5.65 nmol which is at least 2.27 times greater than the mean of 2.27nmol Fe 2+ equivalents per gram fresh weight generated for greenwatercress lines which lack the BWRW mutant allele. This means the redwatercress plant named ‘RW1’ has greater antioxidant power than standardgreen watercress lines.

1-21. (canceled)
 22. A new and distinct variety of red watercress planthaving the characteristics substantially as described and illustratedherein.